Electrochemical energy source integrally formed in a non-conductive casing and method of manufacturing such an electrochemical energy source

ABSTRACT

The invention relates to an electrochemical energy source integrally formed in a non-conductive casing, comprising: a first current collector embedded in said casing and further coupled to an anode, a second current collector embedded in said casing and coupled to a cathode, and an electrolyte and a separator between said anode and said cathode, wherein the casing comprises a portion of a housing of an electronic device. The invention further relates to a method of manufacturing an electrochemical energy source integrally formed in a non-conductive casing, wherein the casing comprises a portion of a housing of an electronic device, comprising the steps of: A) applying at least one electrochemical cell to said casing, which electrochemical cell comprises an anode, and a cathode, B) realizing a suitable configuration for said electrochemical cell, C) applying an electrolyte to said casing, and D) adapting the orientation of said casing such that said formed electrochemical energy source is at least substantially surrounded by said casing.

The invention relates to an electrochemical energy source integrallyformed in a non-conductive casing, comprising: a first current collectorembedded in said casing and further coupled to an anode, a secondcurrent collector embedded in said casing and coupled to a cathode, andan electrolyte and a separator between said anode and said cathode,wherein the casing comprises a portion of a housing of an electronicdevice. The invention further relates to a method of manufacturing anelectrochemical energy source integrally formed in a non-conductivecasing, wherein the casing comprises a portion of a housing of anelectronic device, comprising the steps of: A) applying at least oneelectrochemical cell to said casing, which electrochemical cellcomprises an anode and a cathode, B) realizing a suitable configurationfor said electrochemical cell, C) applying an electrolyte to saidcasing, and D) adapting the orientation of said casing such that saidformed electrochemical energy source is at least substantiallysurrounded by said casing.

An electrochemical energy source, such as a battery, which is integratedin a part of a housing of an electrical appliance is disclosed in theAmerican patent publication U.S. Pat. No. 5,180,645. Providing anintegrated battery (permanently) incorporated into or forming part of anappliance housing has numerous advantages. An integrated battery resultscommonly in a smaller overall size, lighter overall weight, and lowerfabrication cost of the electronic device. However, these advantages ofthe known electrochemical energy source which is integrally formed witha part of a housing of an electronic device are counterbalanced byseveral drawbacks. One of the drawbacks is the relatively restrictivedegree of freedom of design because the choice of a desirable shapeand/or format is extremely limited, i.e. to exclusively flat batteries.Therefore, the shape of the housing of said electronic device iscommonly adapted to the shape and format of batteries suitable for thatspecific device.

It is an object of the present invention to provide an improvedelectrochemical energy source which can be applied in an electronicdevice of any shape, i.e. without the described drawback and preservingthe advantages of the prior art.

The object is achieved by an electrochemical source as described in thepreamble and characterized in that the electrochemical energy source hasa curved, planar geometry. A major advantage of the electrochemicalenergy source having a curved, planar geometry is that any desired shapeof said electrochemical energy source can be realized, so that thefreedom of choice as regards shape and size of said electrochemicalenergy source is many times greater than the freedom offered by thestate of the art. The geometry of said electrochemical energy source canthus be adapted to spatial limitations imposed by any electricalapparatus in which the battery can be used, contrary to the techniquesknown of the prior art. Electrical apparatuses can now be moreefficiently spatially configured in many cases because of the greaterfreedom of the choice of the geometry of the electrochemical energysource; this may lead to a saving of space in and greater freedom ofdesign of the apparatus. It is to be noted that the curved planargeometry results in a curved battery which has a curved planar shapewhich may be concave/convex or wavy. However, it also imaginable for aperson skilled in the art to apply an angular battery which has a hookedshape. The electrochemical energy source according to the invention maycomprise rechargeable batteries, such as Li- or NiMH-batteries,non-rechargeable batteries, and supercapacitors. Said casing maycomprise any non-conductive material, but is preferably manufactured ofpolymer, ceramic, composites, glass, metal provided with anon-conductive layer, or wood. The electrolyte may be formed by a solidstate electrolyte. In this case the separator is commonly formed by thesolid-state electrolyte. Preferably, a liquid-state electrolyte is usedin the electrochemical energy source according to the invention. In thisembodiment the separator is commonly soaked with said liquid-stateelectrolyte.

In a preferred embodiment, the electrochemical energy source comprises alamination of said anode and said cathode, characterized in that thelamination has a curved shape such that the lamination is situated inone curved plane. Comparatively thin and elongated laminates can thus beprovided in a relatively simple manner.

In another preferred embodiment, the electrochemical energy sourcecomprises at least one assembly of electrochemical cells electricallycoupled together, each cell comprising said anode, said first currentcollector, said cathode, said second current collector, saidelectrolyte, and said separator situated between said anode and saidcathode, and insulation means for insulating one cell within saidassembly from another cell within said assembly. Each assembly ofelectrochemical cells or each single electrochemical cell enclosed in aseparate housing is also known as a battery. Each cell or each batterymay be manufactured, for example, in advance and may be applied in theenergy source when desired. The shape of each cell and each battery canbe arbitrary. The overall assembly of cells (and batteries) determinesthe final shape of the electrochemical energy source. Preferably, moreassemblies of cells and/or batteries electrically coupled together areapplied. In a particular preferred embodiment, a pack of batteries isapplied, said batteries being electrically coupled together, whereineach battery comprises at least one electrochemical cell. Said pack canthus have any desired shape determined by the orientation of batteriesin said pack. In a preferred embodiment, at least part of saidassemblies or pack is formed by conventional batteries. In this wayconventional batteries can be use for forming the electrochemical energysource according to the invention. Said conventional batteries may alsobe formed by a specific configuration of one or more cells. In aparticular alternative embodiment, said battery comprises a specificsingle electrochemical cell, also known as a “bicell”. These bicells orother batteries may manufactured, for example, by the known “Bellcore”technology, “gel” technology, or “Lithylene” technology. It must benoted that, if more batteries are applied, the batteries may beelectrically coupled either serially or in parallel. The electrochemicalcells within each assembly or battery may also be coupled electricallyin a manner (serial or parallel) that depends on the needs of (saidhousing of) said electronic device. Thus, within the scope of thepresent invention different configurations of cells and batteries withdifferent electrical connections may be used, which fit differentelectronic devices having different requirements.

The invention also relates to a method of the kind in accordance withthe invention, characterized in that a suitable configuration for saidelectrochemical cell according to step B) is realized such that saidelectrochemical cell exhibits a curved, planar geometry. The advantagesof a curved, planar geometry were described above. Said anode andcathode may be provided on the casing in various manners. A commonmanner of applying the active electrodes on the casing is by physicaldeposition techniques and by silkscreen printing and painting. It isalso imaginable to apply conventional (porous) electrodes. The adapationof the configuration of said casing according to step D) may berealized, for example, by (ultrasonic) welding, diode “lasering”,mechanical deformation, thermal treatment, or polymerization ofliquid-state polymers. As was mentioned above, it is imaginable to applyconventional (pre-assembled) batteries, such as the aforementionedbicells and batteries, to the casing according to step A). Theapplication of said electrolyte according to step C) may be realized ina conventional manner. Optionally, the application of said electrolyteaccording to step C) is achieved by a vacuum treatment. If saidelectrolyte is a solid-state electrolyte, said solid-state electrolytewill usually also form a separator for separating said anode and saidcathode. If a liquid-state electrolyte is used, an additional separatormust be applied. The application of a (separate) separator may beincorporated in step A), but is preferably incorporated in step C). Saidseparator may either comprise a single separator as used, for example,in Li-ion and NiMH batteries, or comprise a separator adapted forlamination as used, for example, in Li-ion and NiMH based on theBellcore technology, polymer gel technology, Lithylenesemi-manufactures, and “UHMW” technology. If a separator adapted forlamination is used, mechanically stable batteries can be formed in situby subjecting said formed batteries to a thermal treatment.

In a preferred embodiment, said electrochemical cell comprises animpermeable sheet surrounding said anode and said cathode. Theimpermeable sheet may either be applied in advance in the casing or itmay be applied to said electrochemical cell before said cell is appliedto said casing according to step A). In particular, the impermeablesheet is adapted to prevent leakage of a (liquid-state) electrolyte fromsaid cell on the one hand and prevent intrusion of moisture and air fromthe local atmosphere into said cell on the other hand. Said impermeablesheet may be manufactured as an assembly of metal and/or polymer sheets.Optionally, the impermeable sheet is integrated with the casing of theelectrochemical energy source during (injection) molding of said casing.

During the application of said electrochemical cell to said casingaccording to step A), multiple electrochemical cells are applied to saidcasing. The electrochemical cells are electrically coupled togetherthereby so as to form a battery. In this manner more batteries can beapplied to said casing, each battery comprising more electrochemicalcells. Said batteries are electrically coupled in series or in parallel.The coupling of cells is preferably realized in advance. As was notedabove, said cells may comprise pre-assembled cells or may be made insitu.

In a last preferred embodiment, the electrochemical cell is subjected toa thermal treatment before said electrolyte and separator are applied tosaid casing according to step C). A stable electrochemical cell can becreated in this manner. Possible techniques for forming a mechanicallystable cell or battery of cells have been mentioned above.

The invention will be illustrated with the following non-restrictiveexamples.

FIG. 1 shows a curved battery which is permanently positioned in andcompletely integrated with a housing of a domestic mixer; and

FIG. 2 shows a curved battery of pre-assembled electrochemical cellswhich is integrated in a chamber of a housing of a celest, an apparatusfor removing cellulitis formed on body parts.

FIG. 1 shows a curved battery 1 which is permanently positioned in andcompletely integrated with a housing 2 of a domestic mixer 3. Saidcurved battery 1 is adapted to the need of the appliance, in particularsaid mixer 3, to accommodate an electrochemical energy source in anefficient and less voluminous manner. Said curved battery 1 may be ofvarious types, but is preferably rechargeable in this application. Saidcurved battery 1 comprises an assembly of an anode, a cathode, anelectrolyte, and separator means, which assembly is not shown in FIG. 1.Said assembly is hermetically packed in an impermeable sheet 4 toprevent leakage of liquid from said battery 1 on the one hand and toprevent intrusion of air, moisture, and other substances into saidbattery on the other hand. The method of manufacturing said battery 1 insaid housing 2 as well as further advantages have been described indetail above.

FIG. 2 shows a curved battery 5 of pre-assembled electrochemical cells 6which is integrated in a chamber 7 of a housing 8 of a celest 9, anapparatus for removing cellulitis formed on body parts. The cells 6 areall (electrically) serially coupled by means of conductive wires 10.Preferably, all cells 6 are rechargeable. The advantage of thisembodiment is that a curved battery 5 can be formed with conventionaland relatively cheap batteries, which, in general, can be adapted to therequirements of and internal space in a housing of an electronic device.Noted is that said curved battery 5 is fixed permanently in said chamber7 of said housing 8. The provision of said curved battery 5 built intosaid housing 8 results commonly in a smaller overall size, lighteroverall weight, and lower fabrication cost of said celest cleaner 9.

1. Electrochemical energy source integrally formed in a non-conductivecasing, comprising: a first current collector embedded in said casingand further coupled to an anode, a second current collector embedded insaid casing and coupled to a cathode, and an electrolyte and a separatorbetween said anode and said cathode, wherein the casing comprises aportion of a housing of an electronic device, characterized in that theelectrochemical energy source has a curved, planar geometry. 2.Electrochemical energy source according to claim 1, characterized inthat the electrochemical energy source comprises a lamination of saidanode and said cathode, characterized in that the lamination has acurved shape such that the lamination is situated in one plane. 3.Electrochemical energy source according to claims 1, characterized inthat said electrolyte is a liquid-state electrolyte.
 4. Electrochemicalenergy source according to claim 1, characterized in that theelectrochemical energy source comprises at least one assembly ofelectrochemical cells electrically coupled together, each cellcomprising said anode, said first current collector, said cathode, saidsecond current collector, and said electrolyte and said separatorsituated between said anode and said cathode, and insulation means forinsulating one cell within said assembly from another cell within saidassembly.
 5. Electrochemical energy source according to claim 4,characterized in that at least one assembly is formed by a conventionalbattery.
 6. Electrochemical energy source according to claim 4,characterized in that a pack of batteries is provided, said batteriesbeing electrically coupled together, wherein each battery comprises atleast one electrochemical cell.
 7. Method of manufacturing anelectrochemical energy source integrally formed in a non-conductivecasing, wherein the casing comprises a portion of a housing of anelectronic device, comprising the steps of: A) applying at least oneelectrochemical cell to said casing, which electrochemical cellcomprises an anode, and a cathode, B) realizing a suitable configurationfor said electrochemical cell, C) applying an electrolyte to saidcasing, and D) adapting the orientation of said casing such that saidformed electrochemical energy source is at least substantiallysurrounded by said casing, characterized in that the realization of asuitable configuration for said electrochemical cell according to stepB) is achieved such that said electrochemical cell exhibits a curved,planar geometry.
 8. Method according to claim 7, characterized in thatsaid electrochemical cell comprises an impermeable sheet surroundingsaid anode and said cathode.
 9. Method according to claim 7,characterized in that multiple electrochemical cells are applied to saidcasing during the application of said electrochemical cell to saidcasing according to step A).
 10. Method according to claim 7,characterized in that the electrochemical cell is subjected to a thermaltreatment before said electrolyte is applied to said casing according tostep C).